The family of murdered horsewoman Katie Simpson will hear the findings of a watchdog investigation into the failures of the Police Service of Northern Ireland (PSNI).

The Police Ombudsman Service will inform them of its findings on Tuesday.

For several months, the death of Ms. Simpson in 2020 was treated by detectives as a suicide.

Several red flags were missed before her sister’s partner, Jonathan Creswell, was finally charged with her murder.

Creswell was found dead at home while he was on trial in April.

Three women accused of helping him cover up murder was sentenced to suspended sentences.

Ms Simpson, 21, from Tynan in Co Armagh, died six days after being admitted to Altnagelvin Hospital, without ever regaining consciousness.

Creswell, 36, beat her before strangling her.

He called 999 and pretended to have found her hanging from a stairwell.

Police Chief Jon Boutcher acknowledged there were “a number of deficiencies” in the early stages of the police investigation and met with Ms Simpson’s family to apologize.

He told a Northern Ireland Policing Board meeting in August that the PSNI had demonstrated a mindset that was not “professionally inquisitive enough”.

Before Cresswell’s arrest, several people, including those close to Ms. Simpson, had raised concerns about him.

He had already been sentenced for an attack on a woman in 2010.

The Ombudsman’s investigation, which began in March 2021, resulted in a 1,400-page file being sent to the PSNI.

She found misconduct by a number of officers, and their cases were dealt with by the PSNI’s professional standards unit.

The inquest followed a number of complaints from Ms Simpson’s family relating to the failure of police to treat her death as a murder at an earlier stage.

They are taking civil action against the PSNI.

It appears that a number of other complaints relating to this matter have been lodged with the Ombudsman more recently.

They are now under investigation.